<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<HTML LANG="EN-US">
<HEAD>
<TITLE>VT100.net: VT330/VT340 Programmer Reference Manual</TITLE>
<LINK HREF="vt330.css" TYPE="text/css" REL="stylesheet">
</HEAD>
<BODY>
<DIV CLASS="navbar"><A HREF="http://vt100.net/"><IMG CLASS="button" SRC="vt100.net-logo.png" ALT="VT100.net" HEIGHT="16" WIDTH="102"></A> VT330/VT340 Programmer Reference Manual Volume 2: Graphics Programming<TABLE WIDTH="100%">
<COL SPAN="3" WIDTH="33%">
<TBODY>
<TR>
<TD ALIGN="LEFT"><A HREF="chapter2.html">Chapter 2</A></TD>
<TD ALIGN="CENTER"><A HREF="contents.html">Contents</A></TD>
<TD ALIGN="RIGHT"><A HREF="chapter4.html">Chapter 4</A></TD>
</TR>
</TBODY>
</TABLE>
<HR></DIV>
<H1 ID="S3"><SPAN CLASS="chapnum">3</SPAN> Write Control Command</H1>
<P>The write control command controls how the terminal draws images on the
screen. Write control command options let you set attributes and parameters
for writing at the pixel level. You can perform 10 major tasks with write control
commands.</P>
<UL>
<LI>PV multiplication</LI>
<LI>Pattern control</LI>
<LI>Foreground intensity selection</LI>
<LI>Foreground plane control</LI>
<LI>Overlay writing</LI>
<LI>Replace writing</LI>
<LI>Complement writing</LI>
<LI>Erase writing</LI>
<LI>Negative pattern control</LI>
<LI>Shading control</LI>
</UL>
<P>You can use these write controls in other commands, as temporary write controls.
For example, you can use temporary write controls in vector, curve,
screen, and position commands. The terminal uses the temporary setting until
you use a new command or another temporary option. For more information,
see the chapter on the particular command.</P>
<H2 ID="S3.1">PV Multiplication &#8211; M</H2>
<P>This option lets you define a multiplication factor for pixel vector (PV) values
used in moving and drawing tasks. Normally, a PV value tells the terminal to
move or draw through one screen coordinate in a certain direction. A multiplication
factor of <B>n</B> tells the terminal to move or draw through <B>n</B> coordinates for
each PV value.</P>
<P>You use the following format for the PV multiplication option. For more information,
see the "<A HREF="chapter1.html#S1.11">Pixel Vector (PV) System</A>" section in <A HREF="chapter1.html">Chapter 1</A>.</P>
<DIV CLASS="example"><P>W(M&lt;multiplication factor&gt;)</P></DIV>
<P>where</P>
<DIV CLASS="example"><P><B>W</B> identifies a write control command.</P>
<P><B>M</B> identifies a PV multiplication option.</P>
<P><B>&lt;multiplication factor&gt;</B> is a numeric value to use for the PV multiplication factor.</P></DIV>
<P>You can temporarily change the PV multiplication factor for some commands,
such as position, screen, vector, and circle commands. To select a temporary
value, you use a temporary write control in one of those commands. The temporary
value stays in effect until the next command or temporary write control.
For more information, see the chapter for a specific command.</P>
<H2 ID="S3.2">Pattern Control &#8211; P</H2>
<P>The VT300 has an 8-bit pattern memory that lets you define the appearance of
lines and shaded areas in ReGIS drawings. ReGIS uses this pattern for all
writing tasks. Each bit in the pattern turns one pixel on or off.</P>
<P>For example, suppose you use a vector command to draw a line on the screen.
As the line is drawn, ReGIS reads the pattern memory bit by bit to determine
if the next pixel should be on (1) or off (0). A 1 value sets the pixel to the
foreground shade/color. A 0 value sets the pixel to the background shade/color.</P>
<P>The VT300 starts each writing task from the first position in pattern memory.
The writing cycles through the complete 8-bit pattern, unless you use a new
command key letter. If you want a command to start at the first position of
pattern memory, start the command with a command key letter.</P>
<P>For example, suppose you draw several vectors or curves in a row. Some vectors
or curves must start at the first position of pattern memory. Start those
commands with the command key letter.</P>
<P>The default for pattern memory is all 1s. If you draw a line using the default
pattern, the terminal sets all pixels in the line to the foreground shade/color.
You can change the default pattern with one of the three pattern control
options.</P>
<UL>
<LI>Select standard pattern</LI>
<LI>Specify binary pattern</LI>
<LI>Pattern multiplication</LI>
</UL>
<H3 ID="S3.2.1">Select Standard Pattern</H3>
<P>There are 10 standard write patterns available. You select a pattern by its assigned
value: 0 through 9. You use the following format for the standard pattern
select option.</P>
<DIV CLASS="example"><P>W(P&lt;pattern number&gt;)</P></DIV>
<P>where</P>
<DIV CLASS="example"><P><B>P</B> identifies a pattern control option.</P>
<P><B>&lt;pattern number&gt;</B> is a number (0 through 9) that selects 1 of the 10
standard writing patterns.</P></DIV>
<P><A HREF="#F3-1">Figure 3-1</A> shows how patterns 1 through 9 appear on the screen. Pattern 0 is
all bits off. <A HREF="#T3-1">Table 3-1</A> lists the bit pattern for each standard pattern. <A HREF="#F3-2">Figure 3-2</A>
shows a closer view of each pattern, using a vector that is 24 pixels long.</P>
<TABLE ID="F3-1" CLASS="figure" WIDTH="100%">
<CAPTION>Figure 3-1 Standard Patterns</CAPTION>
<COL ALIGN="CENTER">
<TBODY>
<TR>
<TD><IMG SRC="ma-0675-83.png" ALT=""></TD>
</TR>
</TBODY>
</TABLE>
<TABLE ID="T3-1" CLASS="majortable">
<CAPTION>Table 3-1 Standard Patterns</CAPTION>
<THEAD>
<TR VALIGN="BOTTOM">
<TH>Pattern Number</TH>
<TH>Binary Pattern</TH>
<TH>Description</TH>
</TR>
</THEAD>
<TBODY>
<TR VALIGN="TOP">
<TD>0</TD>
<TD>00000000</TD>
<TD>All-off write pattern</TD>
</TR>
<TR VALIGN="TOP">
<TD>1</TD>
<TD>11111111</TD>
<TD>All-on write pattern</TD>
</TR>
<TR VALIGN="TOP">
<TD>2</TD>
<TD>11110000</TD>
<TD>Dash pattern</TD>
</TR>
<TR VALIGN="TOP">
<TD>3</TD>
<TD>11100100</TD>
<TD>Dash-dot pattern</TD>
</TR>
<TR VALIGN="TOP">
<TD>4</TD>
<TD>10101010</TD>
<TD>Dot pattern</TD>
</TR>
<TR VALIGN="TOP">
<TD>5</TD>
<TD>11101010</TD>
<TD>Dash-dot-dot pattern</TD>
</TR>
<TR VALIGN="TOP">
<TD>6</TD>
<TD>10001000</TD>
<TD>Sparse dot pattern</TD>
</TR>
<TR VALIGN="TOP">
<TD>7</TD>
<TD>10000100</TD>
<TD>Asymmetrical sparse dot pattern</TD>
</TR>
<TR VALIGN="TOP">
<TD>8</TD>
<TD>11001000</TD>
<TD>Sparse dash-dot pattern</TD>
</TR>
<TR VALIGN="TOP">
<TD>9</TD>
<TD>10000110</TD>
<TD>Sparse dot-dash pattern</TD>
</TR>
</TBODY>
</TABLE>
<TABLE ID="F3-2" CLASS="figure" WIDTH="100%">
<CAPTION>Figure 3-2 Detailed View of Standard Patterns</CAPTION>
<COL ALIGN="CENTER">
<TBODY>
<TR>
<TD><IMG SRC="ma-0407-86.png" ALT=""></TD>
</TR>
<TR>
<TD><TABLE CLASS="command-example" FRAME="BORDER" RULES="GROUPS" CELLSPACING="0" CELLPADDING="8">
<COL ALIGN="RIGHT">
<COL ALIGN="LEFT">
<TBODY>
<TR>
<TD COLSPAN="2" ALIGN="CENTER">NOTES</TD>
</TR>
</TBODY>
<TBODY>
<TR VALIGN="TOP">
<TD>1.</TD>
<TD>All patterns are shown with multiplication value of 1 and negative pattern control off.</TD>
</TR>
<TR VALIGN="TOP">
<TD>2.</TD>
<TD>All patterns are shown for 3 reads of pattern memory, with 1st read starting at the 1st bit.</TD>
</TR>
<TR VALIGN="TOP">
<TD>3.</TD>
<TD>When adjacent pixels are on, they appear as a solid line on the screen.</TD>
</TR>
</TBODY>
</TABLE></TD>
</TR>
</TBODY>
</TABLE>
<H3 ID="S3.2.2">Specify Binary Pattern</H3>
<P>This option lets you create your own patterns, rather than using a standard
pattern. The command format is similar to the format for the select standard
pattern option. The difference is that you use a specific binary pattern instead
of a standard pattern number. You use the following format for using a binary
pattern.</P>
<DIV CLASS="example"><P>W(P&lt;binary pattern&gt;)</P></DIV>
<P>where</P>
<DIV CLASS="example"><P><B>P</B> identifies a pattern control option.</P>
<P><B>&lt;binary pattern&gt;</B> is a pattern of 1 and 0 bits, from 2 to 8 bits long.</P></DIV>
<P>You can use binary patterns up to 8 bits long (the size of pattern memory). If
you specify more than 8 bits, the terminal uses only the last 8 bits of your
pattern. If you specify less than 8 bits, the terminal repeats as much of your
pattern as it can in the remaining bits of pattern memory.</P>
<P>Patterns of 2, 4, or 8 bits will repeat as full subunits within the 8-bit pattern
memory. Patterns of 3, 5, 6, or 7 bits will only repeat as far as possible.</P>
<P><A HREF="#F3-3">Figure 3-3</A> shows examples of patterns you can create. Each pattern is a vector
24 pixels long. You can see from this figure that patterns of 3, 5, 6, and 7 bits
do not repeat as complete subunits.</P>
<TABLE ID="F3-3" CLASS="figure" WIDTH="100%">
<CAPTION>Figure 3-3 Specified Binary Patterns</CAPTION>
<COL ALIGN="CENTER">
<TBODY>
<TR>
<TD><IMG SRC="ma-0408-86.png" ALT=""></TD>
</TR>
<TR>
<TD><TABLE CLASS="command-example" FRAME="BORDER" RULES="GROUPS" CELLSPACING="0" CELLPADDING="8">
<COL ALIGN="RIGHT">
<COL ALIGN="LEFT">
<TBODY>
<TR>
<TD COLSPAN="2" ALIGN="CENTER">NOTES</TD>
</TR>
</TBODY>
<TBODY>
<TR VALIGN="TOP">
<TD>1.</TD>
<TD>P01 results in the same type of pattern as P4, except exactly opposite in on/off values.</TD>
</TR>
<TR VALIGN="TOP">
<TD>2.</TD>
<TD>All patterns are shown with multiplication value of 1 and negative pattern control off.</TD>
</TR>
<TR VALIGN="TOP">
<TD>3.</TD>
<TD>All patterns are shown for 3 reads of pattern memory, with 1st read starting at the 1st bit.</TD>
</TR>
<TR VALIGN="TOP">
<TD>4.</TD>
<TD>When adjacent pixels are on, they appear as a solid line on the screen.</TD>
</TR>
</TBODY>
</TABLE></TD>
</TR>
</TBODY>
</TABLE>
<H3 ID="S3.2.3">Pattern Multiplication</H3>
<P>You can create a writing pattern that is longer than 8 pixels by specifying a
multiplication factor for the 8-bit pattern memory. This factor determines how
many pixels are affected by each bit in the 8-bit pattern memory. The minimum
value is 1, the maximum value is 16. The default value is 2.</P>
<P>You can use a standard pattern or a specified binary pattern. <A HREF="#F3-4">Figure 3-4</A> shows
how multiplication factors can change the patterns from Figures <A HREF="#F3-2">3-2</A> and <A HREF="#F3-3">3-3</A>.</P>
<DIV CLASS="centrefig"><TABLE ID="F3-4" CLASS="figure" WIDTH="600">
<CAPTION>Figure 3-4 Examples of Pattern Multiplication</CAPTION>
<COL ALIGN="CENTER">
<TBODY>
<TR>
<TD><IMG SRC="ma-0402-86.png" ALT=""></TD>
</TR>
<TR>
<TD><TABLE CLASS="command-example" FRAME="BORDER" RULES="GROUPS" CELLSPACING="0" CELLPADDING="8">
<COL ALIGN="RIGHT">
<COL ALIGN="LEFT">
<TBODY>
<TR>
<TD COLSPAN="2" ALIGN="CENTER">NOTES</TD>
</TR>
</TBODY>
<TBODY>
<TR VALIGN="TOP">
<TD>1.</TD>
<TD>All patterns are shown for a single pass through pattern memory,
starting at bit 1, at the specified multiplication value, with negative pattern control off.</TD>
</TR>
<TR VALIGN="TOP">
<TD>2.</TD>
<TD>When adjacent pixels are on, they appear as a solid line on the screen.</TD>
</TR>
</TBODY>
</TABLE></TD>
</TR>
</TBODY>
</TABLE></DIV>
<P>The following examples show the format of pattern multiplication commands.</P>
<DIV CLASS="example"><TABLE CLASS="padded">
<THEAD>
<TR>
<TH CLASS="first">Standard Pattern</TH>
<TH>Specified Binary Pattern</TH>
</TR>
</THEAD>
<TBODY>
<TR>
<TD CLASS="first">W(P4(M5))</TD>
<TD>W(P11000011(M3))</TD>
</TR>
</TBODY>
</TABLE></DIV>
<P>where</P>
<DIV CLASS="example"><P><B>P4</B> identifies a pattern control option and selects standard pattern 4.</P>
<P><B>M5</B> identifies a multiplication option and selects a factor of 5.</P>
<P><B>P11000011</B> identifies a pattern control option and specifies a binary pattern to use for writing.</P>
<P><B>M3</B> identifies a multiplication option and selects a factor of 3.</P></DIV>
<H2 ID="S3.3">Foreground Intensity &#8211; I</H2>
<P>This option selects the foreground color/shade for an image, or for part of an
image. On the VT330, you can use up to four shades in an image. On the
VT340, you can use up to 16 colors/shades. You can only select shades/colors
already loaded into the output map. See the "<A HREF="chapter2.html#S2.4">Output Mapping</A>" section in
<A HREF="chapter2.html">Chapter 2</A>.</P>
<P>You can use three forms of the foreground intensity option, depending on how
you define the color/shade. The following examples show how.</P>
<DIV CLASS="example"><TABLE CLASS="padded">
<THEAD>
<TR>
<TH CLASS="first">Output Map Location</TH>
<TH>RGB Specifier</TH>
<TH>HLS Specifier</TH>
</TR>
</THEAD>
<TBODY>
<TR VALIGN="TOP">
<TD CLASS="first">W(I0)</TD>
<TD>W(I(R))</TD>
<TD>W(I(H180L50S100))</TD>
</TR>
</TBODY>
</TABLE></DIV>
<P>where</P>
<DIV CLASS="example"><P><B>I</B> identifies a foreground intensity.</P>
<P><B>0</B> selects output map location 0 for the foreground color.</P>
<P><B>R</B> is an RGB value that selects the output map location containing the color closest to red.</P>
<P><B>H180L50S100</B> is an HLS value that selects the output map location containing
the color closest to yellow.</P></DIV>
<P>You use this option in combination with the background intensity option for
the screen command. Both options have the same basic format, but start with
different command key letters (W for write command, S for screen command).</P>
<P>The foreground intensity option only selects the shade/color for writing that
follows the option. This feature lets you select different colors for different
parts of an image, without affecting other parts of the same image.</P>
<P>One of the foreground shades/colors is always the same as the background. To
see the background shade/color in the foreground, you must write that shade/color
over another shade/color.</P>
<P>When you select RGB or HLS colors, the VT300 compares your color to the
colors stored in the output map and uses the closest match. However, the terminal's
ability to compare colors is limited. If you select a color that is too
different from those in the output map, the result is unpredictable.</P>
<H2 ID="S3.4">Plane Select Control &#8211; F</H2>
<P>This option lets you select which graphics planes the terminal can write to. The
option defines a code that selects the graphics planes used for writing tasks
such as vectors, curves, and text. The default setting lets the terminal write to
all planes.</P>
<P>The VT330 has a 2-plane bitmap for pixel memory. This means each pixel has
a 2-bit code, 1 bit for each plane. The 2-bit code selects one of four possible
shades stored in the output map. The plane select option defines a 2-bit mask
for the VT330, 1 bit for each plane.</P>
<P>The VT340 has a 4-plane bitmap for pixel memory. This means each pixel has
a 4-bit code, 1 bit in each plane. The 4-bit code selects 1 of 16 possible shades/colors
stored in the output map. The plane select option defines a 4-bit mask
for the VT340, 1 bit for each plane.</P>
<P CLASS="note">NOTE: The screen erase command erases all planes, regardless of the plane
select control setting. See "<A HREF="chapter2.html#S2.7">Screen Erase Control</A>" in <A HREF="chapter2.html">Chapter 2</A>.</P>
<P>You use the following format for the plane select option.</P>
<DIV CLASS="example"><P>W(F&lt;code number&gt;)</P></DIV>
<P>where</P>
<DIV CLASS="example"><P><B>F</B> identifies a plane select control option.</P>
<P><B>&lt;code number&gt;</B> is a number that selects a 2-bit code (VT330) or 4-bit
code (VT340). The code indicates which planes you can write to.</P>
<P>For the VT330, you use a code number from 0 to 3. <A HREF="#T3-2">Table 3-2</A> shows you
which planes these four codes select.</P>
<P>For the VT340, you use a code number from 0 to 15. <A HREF="#T3-3">Table 3-3</A> shows you
which planes these 16 codes select.</P>
<P>Notice that the plane numbers in Tables <A HREF="#T3-2">3-2</A> and <A HREF="#T3-3">3-3</A> correspond to the
binary numbers you use to access the pixels. The number in the <B CLASS="columnheading">Code</B> column
corresponds to the plane you are writing to.</P></DIV>
<P CLASS="note">NOTE: Whether you use a VT330 or VT340, remember to restore writing to all
planes after using 1-plane or no-plane writing.</P>
<TABLE ID="T3-2" CLASS="majortable">
<CAPTION>Table 3-2 Selecting VT330 Planes for Writing*</CAPTION>
<THEAD>
<TR VALIGN="BOTTOM">
<TH>Command</TH>
<TH>Code</TH>
<TH>Planes You Can Write To</TH>
</TR>
</THEAD>
<TBODY>
<TR>
<TD>W(F0)</TD>
<TD>00</TD>
<TD>None</TD>
</TR>
<TR>
<TD>W(F1)</TD>
<TD>01</TD>
<TD>Plane 0</TD>
</TR>
<TR>
<TD>W(F2)</TD>
<TD>10</TD>
<TD>Plane 1</TD>
</TR>
<TR>
<TD>W(F3)</TD>
<TD>11</TD>
<TD>All planes</TD>
</TR>
</TBODY>
</TABLE>
<TABLE ID="T3-3" CLASS="majortable">
<CAPTION>Table 3-3 Selecting VT340 Planes for Writing</CAPTION>
<THEAD>
<TR VALIGN="BOTTOM">
<TH>Command</TH>
<TH>Code</TH>
<TH>Planes You Can Write To</TH>
</TR>
</THEAD>
<TBODY>
<TR>
<TD>W(F0)</TD>
<TD>0000</TD>
<TD>None</TD>
</TR>
<TR>
<TD>W(F1)</TD>
<TD>0001</TD>
<TD>Plane 0</TD>
</TR>
<TR>
<TD>W(F2)</TD>
<TD>0010</TD>
<TD>Plane 1</TD>
</TR>
<TR>
<TD>W(F3)</TD>
<TD>0011</TD>
<TD>Planes 0 and 1</TD>
</TR>
<TR>
<TD>W(F4)</TD>
<TD>0100</TD>
<TD>Plane 2</TD>
</TR>
<TR>
<TD>W(F5)</TD>
<TD>0101</TD>
<TD>Planes 0 and 2</TD>
</TR>
<TR>
<TD>W(F6)</TD>
<TD>0110</TD>
<TD>Planes 1 and 2</TD>
</TR>
<TR>
<TD>W(F7)</TD>
<TD>0111</TD>
<TD>Planes 0, 1, and 2</TD>
</TR>
<TR>
<TD>W(F8)</TD>
<TD>1000</TD>
<TD>Plane 3</TD>
</TR>
<TR>
<TD>W(F9)</TD>
<TD>1001</TD>
<TD>Planes 0 and 3</TD>
</TR>
<TR>
<TD>W(F10)</TD>
<TD>1010</TD>
<TD>Planes 1 and 3</TD>
</TR>
<TR>
<TD>W(F11)</TD>
<TD>1011</TD>
<TD>Planes 0, 1, and 3</TD>
</TR>
<TR>
<TD>W(F12)</TD>
<TD>1100</TD>
<TD>Planes 2 and 3</TD>
</TR>
<TR>
<TD>W(F13)</TD>
<TD>1101</TD>
<TD>Planes 0, 2, and 3</TD>
</TR>
<TR>
<TD>W(F14)</TD>
<TD>1110</TD>
<TD>Planes 1, 2, and 3</TD>
</TR>
<TR>
<TD>W(F15)</TD>
<TD>1111</TD>
<TD>All planes</TD>
</TR>
</TBODY>
</TABLE>
<H3 ID="S3.4.1">Applications of Plane Select Control</H3>
<P>The plane select option changes the write mask to allow writing to each plane
individually. You can use this operation for three main applications.</P>
<UL>
<LI><P><STRONG>Complement writing</STRONG><BR>
Complement writing (described later in this chapter) changes the
bits of the bitmap to their opposite values. For example, in the
VT330, complement writing changes a pixel with an intensity value
of 3 (I3) to 0 (I0). However, if the plane select mask allows writing
only at plane 0, then the new value is I1. if the write mask allows
writing only to plane 1, then the new value is I2.</P></LI>
<LI><P><STRONG>Overlays</STRONG><BR>
You can draw a fixed image in one plane and an overlay for that
image in another plane. For example, you can draw the fixed grid
for a graph in one plane and the data for the graph in another
plane.</P></LI>
<LI><P><STRONG>Alternating displays</STRONG><BR>
The VT330 lets you draw a separate image in each plane, if you
limit each image to one shade. The VT340 lets you draw a separate
image in each plane or any combination of planes. Each image has
full pixel resolution. Remember, each image is limited to the background
value (for pixel off) and a single foreground shade/color value
(for pixel on).</P></LI>
</UL>
<H2 ID="S3.5">Writing Styles</H2>
<P>There are four major writing styles you can use with the write control command:
overlay, replace, complement, and erase. The writing style affects the
way ReGIS draws images into the bitmap (graphics page memory). Each writing
style affects pattern memory differently.</P>
<TABLE CLASS="padded">
<THEAD>
<TR>
<TH CLASS="first">Writing Style</TH>
<TH>Command</TH>
<TH>Part of Pattern Memory Affected</TH>
</TR>
</THEAD>
<TBODY>
<TR VALIGN="TOP">
<TD CLASS="first"><STRONG>Overlay</STRONG></TD>
<TD><STRONG>V</STRONG></TD>
<TD><STRONG>Foreground only (default).</STRONG></TD>
</TR>
<TR VALIGN="TOP">
<TD CLASS="first">Replace</TD>
<TD>R</TD>
<TD>Foreground and background.</TD>
</TR>
<TR VALIGN="TOP">
<TD CLASS="first">Complement</TD>
<TD>C</TD>
<TD>Foreground only. Ignores the foreground intensity.</TD>
</TR>
<TR VALIGN="TOP">
<TD CLASS="first">Erase</TD>
<TD>E</TD>
<TD>Foreground only. Uses background intensity or color to overwrite foreground.</TD>
</TR>
</TBODY>
</TABLE>
<H3 ID="S3.5.1">Overlay Writing &#8211; V</H3>
<P>Overlay writing lets you draw new images in the foreground only. Overlay writing
does not affect the background.</P>
<P>Pattern memory uses bitmap values of 1 for foreground, 0 for background.
Overlay writing only changes those parts of the new image defined by
1s (foreground). Bitmap values do not change for those parts of the new image
defined by 0s (background).</P>
<P>Overlay writing is the default setting for the VT300. You do not have to use a
command to select overlay writing, unless you have used the complement,
erase, or replace writing option.</P>
<P>You use the following format for the overlay writing option.</P>
<DIV CLASS="example"><P>W(V)</P></DIV>
<P>where</P>
<DIV CLASS="example"><P><B>V</B> identifies the overlay writing option.</P></DIV>
<P><A HREF="#F3-5">Figure 3-5</A> shows an example of overlay writing. The shaded gray square is
drawn first, then the slashed square. This figure uses the same basic graphic
image used for the complement, erase, and replace writing examples that follow.
However, the square is shaded light gray instead of black, so you can see
the overlay.</P>
<TABLE ID="F3-5" CLASS="figure" WIDTH="100%">
<CAPTION>Figure 3-5 Overlay Writing Example</CAPTION>
<COL ALIGN="CENTER">
<TBODY>
<TR>
<TD><IMG SRC="ma-0687-83r.png" ALT=""></TD>
</TR>
</TBODY>
</TABLE>
<H3 ID="S3.5.2">Replace Writing &#8211; R</H3>
<P>Replace writing lets you draw new images in the foreground and the background.
In the pattern memory bitmap, replace writing affects 1s (foreground)
and 0s (background).</P>
<P>You use the following format for the replace writing option.</P>
<P CLASS="example">W(R)</P>
<P>where</P>
<P CLASS="example"><B>R</B> identifies the replace writing option.</P>
<P><A HREF="#F3-6">Figure 3-6</A> shows a simple example that uses replace writing to draw a pattern
over a shaded square. First the black square is drawn, then the slashed square
is drawn after using the replace writing option. The slashed square is the same
pattern shown in <A HREF="#F3-5">Figure 3-5</A> for overlay writing. You can compare the effects.</P>
<TABLE ID="F3-6" CLASS="figure" WIDTH="100%">
<CAPTION>Figure 3-6 Replace Writing Example</CAPTION>
<COL ALIGN="CENTER">
<TBODY>
<TR>
<TD><IMG SRC="ma-0685-83r.png" ALT=""></TD>
</TR>
</TBODY>
</TABLE>
<H3 ID="S3.5.3">Complement Writing &#8211; C</H3>
<P>Complement writing lets you write over an image in the "opposite" shade/color.
The word "opposite" refers to the value of the shade/color in the terminal's
bitmap, not the actual color produced on the screen.</P>
<P>Complement writing affects only the foreground, ignoring the setting of the
foreground intensity (I) option. In the pattern memory bitmap, complement
writing only changes the parts of the image defined by 1s (foreground).</P>
<P><A HREF="#F3-7">Figure 3-7</A> shows a simple example of complement writing. First a black square
is drawn, then a slashed square. The slashed square is drawn in black, but
turns white where it overlaps the black square. The rest of the pattern remains
black. The pattern complements both the black square and the white background.</P>
<TABLE ID="F3-7" CLASS="figure" WIDTH="100%">
<CAPTION>Figure 3-7 Complement Writing Example</CAPTION>
<COL ALIGN="CENTER">
<TBODY>
<TR>
<TD><IMG SRC="ma-0682-83r.png" ALT=""></TD>
</TR>
</TBODY>
</TABLE>
<P>The VT330 bitmap provides 2 bits of memory for each pixel, 1 bit for each
plane. Those 2 bits hold a binary code that points to one of four output map
locations. Each output map location defines the intensity value for one shade.</P>
<P>The VT340 bitmap provides 4 bits of memory for each pixel, 1 bit for each
plane. Those 4 bits hold a binary code that points to 1 of 16 output map locations.
Each output map location defines the intensity value for one shade/color.</P>
<P>When you use complement writing to write over a pixel, the terminal changes
the binary code for that pixel to its opposite value. The new binary code selects
a new output map location. The following table shows how complementary writing
changes binary codes. Output map locations are in parentheses.</P>
<DIV CLASS="example"><TABLE CLASS="padded">
<THEAD>
<TR>
<TH CLASS="first" COLSPAN="2">VT330</TH>
<TH COLSPAN="2">VT340</TH>
</TR>
<TR>
<TH CLASS="first">Old value</TH>
<TH>New value</TH>
<TH>Old value</TH>
<TH>New value</TH>
</TR>
</THEAD>
<TBODY>
<TR>
<TD CLASS="first">00 (0)</TD>
<TD>11 (3)</TD>
<TD>0000 (0)</TD>
<TD>1111 (15)</TD>
</TR>
<TR>
<TD CLASS="first">01 (1)</TD>
<TD>10 (2)</TD>
<TD>0011 (3)</TD>
<TD>1100 (12)</TD>
</TR>
<TR>
<TD CLASS="first">10 (2)</TD>
<TD>01 (1)</TD>
<TD>0101 (5)</TD>
<TD>1010 (10)</TD>
</TR>
<TR>
<TD CLASS="first">11 (3)</TD>
<TD>00 (0)</TD>
<TD>1111 (15)</TD>
<TD>0000 (0)</TD>
</TR>
</TBODY>
</TABLE></DIV>
<P>The new shade/color is the shade/color stored in the new output location.</P>
<P>Complement writing only affects the bitmap planes that you can write to. You
select these planes with the plane select control option in this chapter. You can
combine the plane select control and complement writing options. You use the
following formats.</P>
<DIV CLASS="example"><TABLE CLASS="padded">
<THEAD>
<TR VALIGN="BOTTOM">
<TH CLASS="first">Complement Writing<BR>Alone</TH>
<TH>Complement Writing<BR>With the Plane Select Control Option</TH>
</TR>
</THEAD>
<TBODY>
<TR>
<TD CLASS="first">W(C)</TD>
<TD>W(F&lt;code number&gt;&gt;,C)</TD>
</TR>
</TBODY>
</TABLE></DIV>
<P>where</P>
<DIV CLASS="example"><P><B>C</B> identifies the complement writing option. If you use the C option alone,
ReGIS uses the current value of the plane select control (F) option for
complement writing. Complement writing ignores the foreground intensity
setting.</P>
<P><B>F&lt;code number&gt;</B> identifies the plane control option and specifies a code
that selects which planes will be affected by the complement writing option.
See the "<A HREF="#S3.4">Plane Select Control</A>" section in this chapter for a list of codes.</P></DIV>
<P><A HREF="#T3-4">Table 3-4</A> shows how complement writing changes bitmap values
in the VT340, based on the planes selected for writing.</P>
<P><A HREF="#T3-5">Table 3-5</A> lists some examples of how complement writing changes bitmap values
in the VT340, based on the planes selected for writing. The complete table
would be 16 rows &times; 16 columns. The table does not show W(F3,C) through
W(F13,C).</P>
<TABLE ID="T3-4" CLASS="majortable">
<CAPTION>Table 3-4 VT330 Bitmap Complemented Values</CAPTION>
<THEAD>
<TR VALIGN="BOTTOM">
<TH ROWSPAN="2">Initial Value</TH>
<TH COLSPAN="3">Complemented Value</TH>
</TR>
<TR VALIGN="BOTTOM">
<TH>W(C)</TH>
<TH>W(F1,C)</TH>
<TH>W(F2,C)</TH>
</TR>
</THEAD>
<TBODY>
<TR>
<TD>I0<BR>(00)</TD>
<TD>I3<BR>(11)</TD>
<TD>I1<BR>(01)</TD>
<TD>I2<BR>(10)</TD>
</TR>
<TR>
<TD>I1<BR>(01)</TD>
<TD>I2<BR>(10)</TD>
<TD>I0<BR>(00)</TD>
<TD>I3<BR>(11)</TD>
</TR>
<TR>
<TD>I2<BR>(10)</TD>
<TD>I1<BR>(01)</TD>
<TD>I3<BR>(11)</TD>
<TD>I0<BR>(00)</TD>
</TR>
<TR>
<TD>I3<BR>(11)</TD>
<TD>I0<BR>(00)</TD>
<TD>I2<BR>(10)</TD>
<TD>I1<BR>(01)</TD>
</TR>
</TBODY>
</TABLE>
<P CLASS="note">NOTE: The values listed for the <SPAN CLASS="roman">W(C)</SPAN> command assume you can write to
both planes. If you cannot write to both planes, then you can use the <SPAN CLASS="roman">W(F3,C)</SPAN>
command to produce the same values listed for <SPAN CLASS="roman">W(C)</SPAN>.</P>
<TABLE ID="T3-5" CLASS="majortable">
<CAPTION>Table 3-5 VT340 Bitmap Complemented Values</CAPTION>
<THEAD>
<TR VALIGN="BOTTOM">
<TH ROWSPAN="2">Initial Value</TH>
<TH COLSPAN="4">Complemented Value</TH>
</TR>
<TR VALIGN="BOTTOM">
<TH>W(C)</TH>
<TH>W(F1,C)</TH>
<TH>W(F2,C) ...</TH>
<TH>W(F14,C)</TH>
</TR>
</THEAD>
<TBODY>
<TR>
<TD>I0<BR>(0000)</TD>
<TD>I15<BR>(1111)</TD>
<TD>I1<BR>(0001)</TD>
<TD>I2<BR>(0010)</TD>
<TD>I14<BR>(1110)</TD>
</TR>
<TR>
<TD>I1<BR>(0001)</TD>
<TD>I14<BR>(1110)</TD>
<TD>I0<BR>(0000)</TD>
<TD>I3<BR>(0011)</TD>
<TD>I15<BR>(1111)</TD>
</TR>
<TR>
<TD>I2<BR>(0010)</TD>
<TD>I13<BR>(1101)</TD>
<TD>I3<BR>(0011)</TD>
<TD>I0<BR>(0000)</TD>
<TD>I12<BR>(1100)</TD>
</TR>
<TR>
<TD>I3<BR>(0011)</TD>
<TD>I12<BR>(1100)</TD>
<TD>I2<BR>(0010)</TD>
<TD>I1<BR>(0001)</TD>
<TD>I13<BR>(1101)</TD>
</TR>
<TR>
<TD>I4<BR>(0100)</TD>
<TD>I11<BR>(1011)</TD>
<TD>I5<BR>(0101)</TD>
<TD>I6<BR>(0110)</TD>
<TD>I10<BR>(1010)</TD>
</TR>
<TR>
<TD>I5<BR>(0101)</TD>
<TD>I10<BR>(1010)</TD>
<TD>I4<BR>(0100)</TD>
<TD>I7<BR>(0111)</TD>
<TD>I11<BR>(1011)</TD>
</TR>
<TR>
<TD>I6<BR>(0110)</TD>
<TD>I9<BR>(1001)</TD>
<TD>I7<BR>(0111)</TD>
<TD>I4<BR>(0100)</TD>
<TD>I8<BR>(1000)</TD>
</TR>
<TR>
<TD>I7<BR>(0111)</TD>
<TD>I8<BR>(1000)</TD>
<TD>I6<BR>(0110)</TD>
<TD>I5<BR>(0101)</TD>
<TD>I9<BR>(1001)</TD>
</TR>
<TR>
<TD>I8<BR>(1000)</TD>
<TD>I7<BR>(0111)</TD>
<TD>I9<BR>(1001)</TD>
<TD>I10<BR>(1010)</TD>
<TD>I6<BR>(0110)</TD>
</TR>
<TR>
<TD>I9<BR>(1001)</TD>
<TD>I6<BR>(0110)</TD>
<TD>I8<BR>(1000)</TD>
<TD>I11<BR>(1011)</TD>
<TD>I7<BR>(0111)</TD>
</TR>
<TR>
<TD>I10<BR>(1010)</TD>
<TD>I5<BR>(0101)</TD>
<TD>I11<BR>(1011)</TD>
<TD>I8<BR>(1000)</TD>
<TD>I4<BR>(0100)</TD>
</TR>
<TR>
<TD>I11<BR>(1011)</TD>
<TD>I4<BR>(0100)</TD>
<TD>I10<BR>(1010)</TD>
<TD>I9<BR>(1001)</TD>
<TD>I5<BR>(0101)</TD>
</TR>
<TR>
<TD>I12<BR>(1100)</TD>
<TD>I3<BR>(0011)</TD>
<TD>I13<BR>(1101)</TD>
<TD>I14<BR>(1110)</TD>
<TD>I2<BR>(0010)</TD>
</TR>
<TR>
<TD>I13<BR>(1101)</TD>
<TD>I2<BR>(0010)</TD>
<TD>I12<BR>(1100)</TD>
<TD>I15<BR>(1111)</TD>
<TD>I3<BR>(0011)</TD>
</TR>
<TR>
<TD>I14<BR>(1110)</TD>
<TD>I1<BR>(0001)</TD>
<TD>I15<BR>(1111)</TD>
<TD>I12<BR>(1100)</TD>
<TD>I0<BR>(0000)</TD>
</TR>
<TR>
<TD>I15<BR>(1111)</TD>
<TD>I0<BR>(0000)</TD>
<TD>I14<BR>(1110)</TD>
<TD>I13<BR>(1101)</TD>
<TD>I1<BR>(0001)</TD>
</TR>
</TBODY>
</TABLE>
<P CLASS="note">NOTE: The values shown for <SPAN CLASS="roman">W(C)</SPAN> command assume that all planes are enabled for writing.
If all planes are not enabled, then <SPAN CLASS="roman">W(F15,C)</SPAN> produces the same values as <SPAN CLASS="roman">W(C)</SPAN>.</P>
<H3 ID="S3.5.4">Erase Writing &#8211; E</H3>
<P>This option changes the shade/color used for the writing commands that follow
the option. In effect, you erase areas by writing over them with the background
or foreground color. Erase writing remains in effect until you change the writing
option.</P>
<P>Erase writing ignores the bitmap values in the pattern memory. The current
writing pattern remains constant.</P>
<P>You can erase writing with negative writing on or off. With negative writing
off (default), erase writing erases areas by writing over them with the current
background shade/color. With negative writing on, erase writing erases
areas by writing over them with the foreground shade/color.</P>
<P>You use the following format for the basic erase writing option.</P>
<P CLASS="example">W(E)</P>
<P>where</P>
<P CLASS="example"><B>E</B> identifies the erase writing option.</P>
<P><A HREF="#F3-8">Figure 3-8</A> shows the effect that negative writing has on erase writing. The
slashed square is drawn first, then the solid white (A) or black (B) square.
<A HREF="#F3-9">Figure 3-9</A> shows the effect that the foreground select option can have on erase
writing (when negative writing is on).</P>
<DIV CLASS="centrefig"><TABLE ID="F3-8" CLASS="figure" WIDTH="480">
<CAPTION>Figure 3-8 Example of Erase Writing with Negative Pattern Control</CAPTION>
<COL WIDTH="50" ALIGN="RIGHT">
<COL WIDTH="430">
<TBODY>
<TR>
<TD COLSPAN="2"><IMG SRC="ma-0683-83ar.png" ALT=""></TD>
</TR>
<TR VALIGN="TOP">
<TD><SMALL>A)</SMALL>&nbsp;</TD>
<TD><SMALL>Shaded square erased using W(N0), or W(E) if negative writing off (default or previous N0).<BR>&nbsp;</SMALL></TD>
</TR>
<TR>
<TD COLSPAN="2"><IMG SRC="ma-0683-83br.png" ALT=""></TD>
</TR>
<TR VALIGN="TOP">
<TD><SMALL>B)</SMALL>&nbsp;</TD>
<TD><SMALL>Shaded square erased using W(N1,E), or W(E) if negative writing on (previous N1).<BR>&nbsp;</SMALL></TD>
</TR>
</TBODY>
</TABLE></DIV>
<DIV CLASS="centrefig"><TABLE ID="F3-9" CLASS="figure" WIDTH="480">
<CAPTION>Figure 3-9 Example of Erase Writing with Negative Pattern Control and Foreground Specification</CAPTION>
<COL ALIGN="CENTER">
<TBODY>
<TR>
<TD><IMG SRC="ma-0684-83r.png" ALT=""></TD>
</TR>
<TR>
<TD><TABLE CLASS="command-example" FRAME="BORDER" RULES="GROUPS" CELLSPACING="0" CELLPADDING="8">
<TBODY>
<TR>
<TD ALIGN="CENTER">NOTE</TD>
</TR>
</TBODY>
<TBODY>
<TR VALIGN="TOP">
<TD>Erase writing selected by W(N1,E,12), if negative writing off, or W(E,12) if on.</TD>
</TR>
</TBODY>
</TABLE></TD>
</TR>
</TBODY>
</TABLE></DIV>
<H2 ID="S3.6">Negative Pattern Control &#8211; N</H2>
<P>This option lets you reverse the effect of pattern memory. The negative pattern
control changes all 1s in pattern memory to 0s, and changes all 0s to 1s. The
default setting for negative pattern control is off. This option affects the drawing
of all lines, shaded areas, and text.</P>
<P>Usually, the 1 bits in pattern memory select the foreground shade/color for a
pixel, and the 0 bits select the background shade/color. When you turn negative
pattern control on, the reverse is true: the 1 bits select the background, and
the 0 bits select the foreground.</P>
<P>You use the following format for the negative pattern control option.</P>
<P CLASS="example">W(N&lt;0 or 1&gt;)</P>
<P>where</P>
<DIV CLASS="example"><P><B>N</B> identifies a negative pattern control option.</P>
<P><B>&lt;0 or 1&gt;</B> turns the negative pattern control off (0) or on (1).</P></DIV>
<P><A HREF="#F3-10">Figure 3-10</A> shows how the negative pattern control changes the standard
patterns from <A HREF="#F3-2">Figure 3-2</A> and the specified binary patterns from <A HREF="#F3-3">Figure 3-3</A>. <A HREF="#F3-10">Figure
3-10</A> shows the normal pattern (with negative pattern control off), then the reverse
pattern (with negative pattern control on).</P>
<TABLE ID="F3-10" CLASS="figure" WIDTH="100%">
<CAPTION>Figure 3-10 Examples of Negative Patterns</CAPTION>
<COL ALIGN="CENTER">
<TBODY>
<TR>
<TD><IMG SRC="ma-0404-86.png" ALT=""></TD>
</TR>
<TR>
<TD><TABLE CLASS="command-example" FRAME="BORDER" RULES="GROUPS" CELLSPACING="0" CELLPADDING="8">
<COL ALIGN="RIGHT">
<COL ALIGN="LEFT">
<TBODY>
<TR>
<TD COLSPAN="2" ALIGN="CENTER">NOTES</TD>
</TR>
</TBODY>
<TBODY>
<TR VALIGN="TOP">
<TD>1.</TD>
<TD>Each pattern is shown for 2 passes through pattern memory, with a multiplication value of 2.</TD>
</TR>
<TR VALIGN="TOP">
<TD>2.</TD>
<TD>When adjacent pixels are on, they appear as a solid line on the screen.</TD>
</TR>
</TBODY>
</TABLE></TD>
</TR>
</TBODY>
</TABLE>
<H2 ID="S3.7">Shading Control &#8211; S</H2>
<P>This option lets you shade the inside of a graphic object as it is drawn. During
shading commands, vector and curve commands operate as usual. However, as
each point in a vector or curve is drawn, shading occurs from that point to a
point on a <EM>shading reference line</EM>. The shading includes the point being drawn,
as well as the point on the reference line.</P>
<P>The default value for the shading reference line is the horizontal line defined by
the Y-coordinate of the cursor position when you turn shading on. You can select
a different reference line with a position argument to the shading control
option.</P>
<P><A HREF="#F3-11">Figure 3-11</A> shows how shading occurs. This figure shows different phases of a
circle being drawn while the shading control option is on. The figure uses the
default reference line for shading.</P>
<P>You can use patterns or text characters to shade a graphic object. The final
result depends on the setting of several other ReGIS command options.</P>
<TABLE>
<THEAD>
<TR VALIGN="BOTTOM">
<TH>Options</TH>
<TH>Pattern Shading</TH>
<TH>Character Shading</TH>
</TR>
</THEAD>
<TBODY>
<TR VALIGN="TOP">
<TD>Pattern</TD>
<TD>yes</TD>
<TD>no</TD>
</TR>
<TR VALIGN="TOP">
<TD>Pattern multiplication factor</TD>
<TD>yes</TD>
<TD>no</TD>
</TR>
<TR VALIGN="TOP">
<TD>Foreground intensity</TD>
<TD>yes</TD>
<TD>yes</TD>
</TR>
<TR VALIGN="TOP">
<TD>Background intensity</TD>
<TD>yes</TD>
<TD>yes</TD>
</TR>
<TR VALIGN="TOP">
<TD>Plane select</TD>
<TD>yes</TD>
<TD>yes</TD>
</TR>
<TR VALIGN="TOP">
<TD>Negative writing</TD>
<TD>yes</TD>
<TD>yes</TD>
</TR>
<TR VALIGN="TOP">
<TD>Any overlay, erase, complement, or replace writing in effect</TD>
<TD>yes</TD>
<TD>yes</TD>
</TR>
<TR VALIGN="TOP">
<TD>Text command options</TD>
<TD>no</TD>
<TD>yes</TD>
</TR>
</TBODY>
</TABLE>
<P>There are three types of shading controls.</P>
<UL>
<LI>Shading on/off control</LI>
<LI>Shading reference line select</LI>
<LI>Shading character select</LI>
</UL>
<P>The following sections cover each control. Then the text discusses the use of
multiple shading reference lines. You need multiple shading reference lines for
complex graphic images, such as polygons.</P>
<TABLE ID="F3-11" CLASS="figure" WIDTH="100%">
<CAPTION>Figure 3-11 Shading Examples</CAPTION>
<COL ALIGN="CENTER">
<TBODY>
<TR>
<TD><IMG SRC="ma-0689-83.png" ALT=""></TD>
</TR>
<TR>
<TD><TABLE CLASS="command-example" FRAME="BORDER" RULES="GROUPS" CELLSPACING="0" CELLPADDING="8">
<TBODY>
<TR>
<TD ALIGN="CENTER">NOTE</TD>
</TR>
</TBODY>
<TBODY>
<TR>
<TD>The shading reference line would not appear on the screen</TD>
</TR>
</TBODY>
</TABLE></TD>
</TR>
</TBODY>
</TABLE>
<H3 ID="S3.7.1">Shading On/Off Control</H3>
<P>You use the following format for the shading on/off control option.</P>
<P CLASS="example">W(S&lt;0 or 1&gt;)</P>
<P>where</P>
<DIV CLASS="example"><P><B>S</B> identifies the shading control option.</P>
<P><B>&lt;0 or 1&gt;</B> turns shading off (0) or on (1).</P></DIV>
<P>When you turn shading on, the terminal uses all currently selected writing options.
If the pattern is a solid line (P1), a graphic image is completely shaded
at the currently selected intensity (VT330: I0 through I3, VT340: I0 through
I15). The shaded image does not have an apparent outline, other than the contrast
between the background intensity and the foreground intensity.</P>
<P><A HREF="#F3-12">Figure 3-12</A> shows three simple circles shaded with different foreground intensities.
This figure shows that the outline for each circle is formed by the contrast
between the background and the foreground.</P>
<P>If you want an outline, you can simply repeat the circle command with shading
off. <A HREF="#F3-13">Figure 3-13</A> shows the same circles drawn in <A HREF="#F3-12">Figure 3-12</A>. To draw the outlines,
the circle commands are repeated with shading off, and with a different
foreground intensity from that used in shading.</P>
<P>All the figures in this section use the default reference line for shading.
Remember, you automatically define the default reference line when you turn
shading on. When you use default reference lines, you should turn shading on
for each image you shade. Otherwise, the terminal always uses the last reference
line defined.</P>
<DIV CLASS="centrefig"><TABLE ID="F3-12" CLASS="figure" WIDTH="480">
<CAPTION>Figure 3-12 Circle Shading Examples, Without Outlines</CAPTION>
<COL ALIGN="CENTER">
<TBODY>
<TR>
<TD><IMG SRC="ma-0690-83r.png" ALT=""></TD>
</TR>
<TR>
<TD ALIGN="LEFT"><SMALL>NOTE:<BR>
Graphic assumes all output map values are at default shades, background intensity is S(I3), and
write controls are W(F3,N0,V,I0,P1(M2)).<BR>&nbsp;</SMALL></TD>
</TR>
<TR>
<TD><TABLE CLASS="command-example" FRAME="BORDER" RULES="GROUPS" CELLSPACING="0" CELLPADDING="8">
<TBODY>
<TR>
<TD ALIGN="CENTER">COMMANDS</TD>
</TR>
</TBODY>
<TBODY>
<TR VALIGN="TOP">
<TD>P[150,200]<BR>W(S1)<BR>C[+100]<BR>P[400]<BR>W(S1)<BR>C(W(I1))<BR>
[+100]<BR>P[650]<BR>W(S1)<BR>C(W(I2))<BR>[+100]<BR>W(S0)</TD>
</TR>
</TBODY>
</TABLE></TD>
</TR>
</TBODY>
</TABLE></DIV>
<DIV CLASS="centrefig"><TABLE ID="F3-13" CLASS="figure" WIDTH="480">
<CAPTION>Figure 3-13 Circle Shading Examples, with Outlines</CAPTION>
<COL ALIGN="CENTER">
<TBODY>
<TR>
<TD><IMG SRC="ma-0691-83r.png" ALT=""></TD>
</TR>
<TR>
<TD ALIGN="LEFT"><SMALL>NOTE:<BR>
Graphic assumes all output map values are at default shades, background intensity is S(I3), and
write controls are W(F3,N0,V,I0,P1(M2)).<BR>&nbsp;</SMALL></TD>
</TR>
<TR>
<TD><TABLE CLASS="command-example" FRAME="BORDER" RULES="GROUPS" CELLSPACING="0" CELLPADDING="8">
<TBODY>
<TR>
<TD ALIGN="CENTER">COMMANDS</TD>
</TR>
</TBODY>
<TBODY>
<TR VALIGN="TOP">
<TD>P[150,200]<BR>W(S1)<BR>C[+100]<BR>W(S0)<BR>C(W(I1))<BR>[+100]<BR>P[400]<BR>
W(S1)<BR>C(W(I1))<BR>[+100]<BR>W(S0)<BR>C[+100]<BR>P[650]<BR>W(S1)<BR>C(W(I2))<BR>
[+100]<BR>W(S0)<BR>C[+100]</TD>
</TR>
</TBODY>
</TABLE></TD>
</TR>
</TBODY>
</TABLE></DIV>
<P>You can use default reference lines or define your own reference line (next section).
In either case, shading always includes the shading reference line.</P>
<P>For example, <A HREF="#F3-14">Figure 3-14</A> shows a simple graph that is shaded by using the
baseline for a shading reference line. Part of the baseline has disappeared. To
keep the baseline, you can move the cursor up one row before you turn shading
on. <A HREF="#F3-15">Figure 3-15</A> shows how.</P>
<DIV CLASS="centrefig"><TABLE ID="F3-14" CLASS="figure" WIDTH="480">
<CAPTION>Figure 3-14 Graph Shading Example: Shading Through the Graph Baseline</CAPTION>
<COL ALIGN="CENTER">
<TBODY>
<TR>
<TD><IMG SRC="ma-0692-83r.png" ALT=""></TD>
</TR>
<TR>
<TD ALIGN="LEFT"><SMALL>NOTE:<BR>
Graphic assumes all output map values are at default shades, background intensity is S(I3), and
write controls are W(F3,N0,V,I0,P1(M2)).<BR>&nbsp;</SMALL></TD>
</TR>
<TR>
<TD><TABLE CLASS="command-example" FRAME="BORDER" RULES="GROUPS" CELLSPACING="0" CELLPADDING="8">
<TBODY>
<TR>
<TD ALIGN="CENTER">COMMANDS</TD>
</TR>
</TBODY>
<TBODY>
<TR VALIGN="TOP">
<TD>P[100,100]<BR>V[,+300]<BR>[+400]<BR>P[-300]<BR>W(S1)<BR>V(W(I2))<BR>[,-200]<BR>[+100]<BR>[,+200]<BR>W(S0)<BR>V[,-200]<BR>[-100]<BR>[,+200]</TD>
</TR>
</TBODY>
</TABLE></TD>
</TR>
</TBODY>
</TABLE></DIV>
<DIV CLASS="centrefig"><TABLE ID="F3-15" CLASS="figure" WIDTH="480">
<CAPTION>Figure 3-15 Graph Shading Example: Shading up to the Graph Baseline</CAPTION>
<COL ALIGN="CENTER">
<TBODY>
<TR>
<TD><IMG SRC="ma-0694-83r.png" ALT=""></TD>
</TR>
<TR>
<TD ALIGN="LEFT"><SMALL>NOTE:<BR>
Graphic assumes all output map values are at default shades, background intensity is S(I3), and
write controls are W(F3,N0,V,I0,P1(M2)).<BR>&nbsp;</SMALL></TD>
</TR>
<TR>
<TD><TABLE CLASS="command-example" FRAME="BORDER" RULES="GROUPS" CELLSPACING="0" CELLPADDING="8">
<TBODY>
<TR>
<TD ALIGN="CENTER">COMMANDS</TD>
</TR>
</TBODY>
<TBODY>
<TR VALIGN="TOP">
<TD>P[100,100]<BR>V[,+300]<BR>[+400]<BR>P[-300,-1]<BR>W(S1)<BR>V(W(I2))<BR>[,-200]<BR>[+100]<BR>[,+200]<BR>W(S0)<BR>V[,-200]<BR>[-100]<BR>[,+200]</TD>
</TR>
</TBODY>
</TABLE></TD>
</TR>
</TBODY>
</TABLE></DIV>
<P>You can change the shading pattern by selecting a writing pattern other than a
solid line (P1). <A HREF="#F3-16">Figure 3-16</A> shows an example. In this figure, the circle is
shaded with a dashed line pattern (P2). As shown, this pattern breaks the circle
into horizontal bars.</P>
<P CLASS="note">NOTE: If you want to change the pattern for shading, you must specify the
new pattern before you turn shading on.</P>
<TABLE ID="F3-16" CLASS="figure" WIDTH="100%">
<CAPTION>Figure 3-16 Circle Shading Example: Nonsolid Pattern</CAPTION>
<COL ALIGN="CENTER">
<COL WIDTH="460" ALIGN="RIGHT">
<TBODY>
<TR>
<TD><TABLE CLASS="command-example" FRAME="BORDER" RULES="GROUPS" CELLSPACING="0" CELLPADDING="8">
<TBODY>
<TR>
<TD ALIGN="CENTER">COMMANDS</TD>
</TR>
</TBODY>
<TBODY>
<TR VALIGN="TOP">
<TD>P[400,200]<BR>C(W(P2),(S1))<BR>[+60]</TD>
</TR>
</TBODY>
</TABLE></TD>
<TD><IMG SRC="ma-0695-83r.png" ALT=""></TD>
</TR>
<TR>
<TD></TD>
<TD ALIGN="LEFT"><SMALL>NOTE:<BR>
Graphic assumes all output map values are at default shades, background intensity is S(I3), and
write controls are W(F3,N0,V,I0,P1(M2)).<BR>&nbsp;</SMALL></TD>
</TR>
</TBODY>
</TABLE>
<H3 ID="S3.7.2">Select Shading Reference Line</H3>
<P>This option lets you define your own shading reference line. You can use the
default shading reference line to shade most images. However, a default reference
line will not work for some graphic objects.</P>
<P>For example you cannot use a default reference line to shade a circle with a
specified center. In <A HREF="#F3-17">Figure 3-17</A>, a shaded circle is drawn with a center at [325,125].
Then the outline of the circle is drawn with shading off. As shown, the
default shading reference line produces shading outside the circle.</P>
<TABLE ID="F3-17" CLASS="figure" WIDTH="100%">
<CAPTION>Figure 3-17 Incorrect Shading Example: Default Shading Reference Value Used with Center at Specified Position Option</CAPTION>
<COL ALIGN="CENTER">
<COL WIDTH="460" ALIGN="RIGHT">
<TBODY>
<TR>
<TD><TABLE CLASS="command-example" FRAME="BORDER" RULES="GROUPS" CELLSPACING="0" CELLPADDING="8">
<TBODY>
<TR>
<TD ALIGN="CENTER">COMMANDS</TD>
</TR>
</TBODY>
<TBODY>
<TR VALIGN="TOP">
<TD>P[250,200]<BR>W(S1)<BR>C(W(I2))<BR>(C)[325,125]<BR>W(S0)<BR>C(C)[325,125]</TD>
</TR>
</TBODY>
</TABLE></TD>
<TD><IMG SRC="ma-0696-83r.png" ALT=""></TD>
</TR>
<TR>
<TD></TD>
<TD ALIGN="LEFT"><SMALL>NOTE:<BR>
Graphic assumes all output map values are at default shades, background intensity is S(I3), and
write controls are W(F3,N0,V,I0,P1(M2)).<BR>&nbsp;</SMALL></TD>
</TR>
</TBODY>
</TABLE>
<P>You can define a horizontal or vertical reference line, using one X- or Y-coordinate.
You can use an absolute or relative value for the coordinate. You
use the following formats for defining a new shading reference line.</P>
<DIV CLASS="example"><TABLE CLASS="padded">
<THEAD>
<TR>
<TH CLASS="first">Vertical Reference Line</TH>
<TH>Horizontal Reference Line</TH>
</TR>
</THEAD>
<TBODY>
<TR>
<TD CLASS="first">W(S(X)[&lt;X position&gt;])</TD>
<TD>W(S[,&lt;Y position&gt;])</TD>
</TR>
</TBODY>
</TABLE></DIV>
<P>where</P>
<DIV CLASS="example"><P><B>S</B> identifies a shading control option.</P>
<P><B>(X)</B> selects a vertical (X-axis) shading reference line.</P>
<P><B>[&lt;X position&gt;]</B> is the X-coordinate value to use for the vertical reference
line. If you include a Y-coordinate ([X,Y]), ReGIS ignores the Y-coordinate.</P>
<P>If you omit the X-coordinate ([] or [,Y]), ReGIS assumes a [+0] coordinate
and uses the X-coordinate of the current active position.</P>
<P><B>[,&lt;Y position&gt;]</B> is a Y-coordinate value to use for a horizontal reference
line. If you include an X-coordinate ([X,Y]), ReGIS ignores the X-coordinate.</P>
<P>If you omit the Y-coordinate ([] or [X]), ReGIS assumes a [+0] coordinate
and uses the Y-coordinate of the current active position. Omitting the Y-coordinate
is the same as using the W(S1) command.</P></DIV>
<P><A HREF="#F3-18">Figure 3-18</A> shows one way to change the shading of the circle in <A HREF="#F3-17">Figure 3-17</A>,
by defining a new shading reference line.</P>
<TABLE ID="F3-18" CLASS="figure" WIDTH="100%">
<CAPTION>Figure 3-18 Correct Shading Example: Shading Reference Line Select Option Used with Circle with Center at Specified Position Option</CAPTION>
<COL ALIGN="CENTER">
<COL WIDTH="460" ALIGN="RIGHT">
<TBODY>
<TR>
<TD><TABLE CLASS="command-example" FRAME="BORDER" RULES="GROUPS" CELLSPACING="0" CELLPADDING="8">
<TBODY>
<TR>
<TD ALIGN="CENTER">COMMANDS</TD>
</TR>
</TBODY>
<TBODY>
<TR VALIGN="TOP">
<TD>P[250,200]<BR>W(S1[,125])<BR>C(W(I2))<BR>(C)[325,125]<BR>W(S0)<BR>C(C)[325,125]</TD>
</TR>
</TBODY>
</TABLE></TD>
<TD><IMG SRC="ma-0697-83r.png" ALT=""></TD>
</TR>
<TR>
<TD></TD>
<TD ALIGN="LEFT"><SMALL>NOTE:<BR>
Graphic assumes all output map values are at default shades, background intensity is S(I3), and
write controls are W(F3,N0,V,I0,P1(M2)).<BR>&nbsp;</SMALL></TD>
</TR>
</TBODY>
</TABLE>
<P>You can use different reference lines to draw shaded objects with a minimum
of vector or curve commands. <A HREF="#F3-19">Figure 3-19</A> shows some images drawn with
shading reference lines that use a Y-coordinate. <A HREF="#F3-20">Figure 3-20</A> shows some images
drawn with shading reference lines that use an X-coordinate.</P>
<DIV CLASS="centrefig"><TABLE ID="F3-19" CLASS="figure" WIDTH="480">
<CAPTION>Figure 3-19 Drawing Images with Shading Reference Line Select Option (Y-Position Value)</CAPTION>
<COL ALIGN="CENTER">
<TBODY>
<TR>
<TD><IMG SRC="ma-0698-83r.png" ALT=""></TD>
</TR>
<TR>
<TD ALIGN="LEFT"><SMALL>NOTE:<BR>Graphic assumes all ouput map values are at default shades, background
intensity is S(I3), and write controls are W(F3, N0, V, I0, P1(M2)).<BR>&nbsp;</SMALL></TD>
</TR>
<TR>
<TD><TABLE CLASS="command-example" FRAME="BORDER" RULES="GROUPS" CELLSPACING="0" CELLPADDING="8">
<TBODY>
<TR>
<TD ALIGN="CENTER">COMMANDS</TD>
</TR>
</TBODY>
<TBODY>
<TR VALIGN="TOP">
<TD>P[125,125]<BR>W(S1[,+25])<BR>C(A90)[,-100]<BR>P[+175,+75]<BR>W(S1[,300])<BR>V[+100]<BR>P[500]<BR>W(S1[,-100])<BR>C(A-45C)[,+100]<BR>P[,300]<BR>W(S1[,+100])<BR>V[700,400]<BR>W(S0)</TD>
</TR>
</TBODY>
</TABLE></TD>
</TR>
</TBODY>
</TABLE></DIV>
<TABLE ID="F3-20" CLASS="figure" WIDTH="100%">
<CAPTION>Figure 3-20 Drawing Images with Shading Reference Line Select Option (X-Position Value)</CAPTION>
<COL ALIGN="CENTER">
<TBODY>
<TR>
<TD><IMG SRC="ma-0699-83.png" ALT=""></TD>
</TR>
<TR>
<TD><TABLE CLASS="command-example" FRAME="BORDER" RULES="GROUPS" CELLSPACING="0" CELLPADDING="8">
<TBODY>
<TR>
<TD ALIGN="CENTER">COMMANDS</TD>
</TR>
</TBODY>
<TBODY>
<TR VALIGN="TOP">
<TD>P[150,100]<BR>W(S(X)[+50]<BR>C(A45)[50,150]<BR>P[+150,+100]<BR>W(S(X)[400])<BR>V[-100,+100]<BR>P[550,100]<BR>W(S(X)[590])<BR>C[+60]<BR>P[,+200]<BR>W(S(X)[+100])<BR>V[,+100]<BR>W(S0)</TD>
</TR>
</TBODY>
</TABLE></TD>
</TR>
</TBODY>
</TABLE>
<P>The type of reference line you use has no effect on the way shading patterns
are oriented. <A HREF="#F3-21">Figure 3-21</A> shows a circle shaded with a dashed line pattern (P2)
and an X-coordinate for the reference line. This circle is identical to the circle
in <A HREF="#F3-16">Figure 3-16</A>, drawn with the default reference line. So, you can shade complex
objects using horizontal or vertical reference lines, while maintaining the
same pattern.</P>
<P CLASS="note">NOTE: For compatibility with previous ReGIS products, use only horizontal
shading reference lines.</P>
<TABLE ID="F3-21" CLASS="figure" WIDTH="100%">
<CAPTION>Figure 3-21 Nonsolid Pattern Shading Example, Using X-Position Value for Shading Reference Line Select Option</CAPTION>
<COL ALIGN="CENTER">
<COL WIDTH="460" ALIGN="RIGHT">
<TBODY>
<TR>
<TD><TABLE CLASS="command-example" FRAME="BORDER" RULES="GROUPS" CELLSPACING="0" CELLPADDING="8">
<TBODY>
<TR>
<TD ALIGN="CENTER">COMMANDS</TD>
</TR>
</TBODY>
<TBODY>
<TR VALIGN="TOP">
<TD>P[400,200]<BR>C(W(P2,S(X)[400]))<BR>[+60]</TD>
</TR>
</TBODY>
</TABLE></TD>
<TD><IMG SRC="ma-0700-83r.png" ALT=""></TD>
</TR>
<TR>
<TD></TD>
<TD ALIGN="LEFT"><SMALL>NOTE:<BR>
Graphic assumes all output map values are at default shades, background intensity is S(I3), and
write controls are W(F3,N0,V,I0,P1(M2)).<BR>&nbsp;</SMALL></TD>
</TR>
</TBODY>
</TABLE>
<H3 ID="S3.7.3">Select Shading Character</H3>
<P>This argument lets you shade objects by using text characters instead of patterns.
You can use characters from the standard character sets or from an alternate
set you load into the terminal.</P>
<P>You use the following format for the shading character select argument. You
must use single or double quotes to enclose the character selected for shading.</P>
<P CLASS="example">W(S'&lt;character&gt;')</P>
<P>where</P>
<DIV CLASS="example"><P><B>S</B> identifies the shading control option.</P>
<P><B>' '</B> are quotation marks that enclose the selected shading character.</P>
<P><B>&lt;character&gt;</B> selects the character cell to use for shading. The actual character
used depends on the format stored in the selected character cell.</P></DIV>
<P>You can use text commands to select a character set and character size for the
shading character. Otherwise, the terminal uses the ISO Latin-1 character set
and a default character size of S1. <A HREF="chapter7.html">Chapter 7</A> describes text commands and
character sizes.</P>
<P>You can use character shading to produce halftone effects. This feature is useful
when designing images for devices that have only two intensity values, such
as dot-matrix printers. To produce the gray scale effects, you use different-density
characters for shading. You must design and load these characters into
the terminal. <A HREF="chapter8.html">Chapter 8</A> describes how to design and load characters.</P>
<P>No matter what type of shading character you use, the terminal only displays
the top 8 &times; 8 matrix of the 8 &times; 10 character cell.</P>
<P><A HREF="#F3-22">Figure 3-22</A> shows a circle shaded with Xs. In this example, a text command
selects the size of the X character, but not the character set. The terminal uses
the X from the standard character set. The terminal also uses the default shading
reference line.</P>
<TABLE ID="F3-22" CLASS="figure" WIDTH="100%">
<CAPTION>Figure 3-22 Shading Character Select Example</CAPTION>
<COL ALIGN="CENTER">
<COL WIDTH="460" ALIGN="RIGHT">
<TBODY>
<TR>
<TD><TABLE CLASS="command-example" FRAME="BORDER" RULES="GROUPS" CELLSPACING="0" CELLPADDING="8">
<TBODY>
<TR>
<TD ALIGN="CENTER">COMMANDS</TD>
</TR>
</TBODY>
<TBODY>
<TR VALIGN="TOP">
<TD>P[400,200]<BR>T(S1)<BR>W(S'X')<BR>C[+60]<BR>W(S0)</TD>
</TR>
</TBODY>
</TABLE></TD>
<TD><IMG SRC="ma-0701-83r.png" ALT=""></TD>
</TR>
<TR>
<TD></TD>
<TD ALIGN="LEFT"><SMALL>NOTE:<BR>
Graphic assumes all output map values are at default shades, background intensity is S(I3), and
write controls are W(F3,N0,V,I0,P1(M2)).<BR>&nbsp;</SMALL></TD>
</TR>
</TBODY>
</TABLE>
<P>You can also use horizontal or vertical shading reference lines, without changing
the shading pattern for complex images. You use the following formats to
select a shading character and a shading reference line in the same command.</P>
<DIV CLASS="example"><TABLE CLASS="padded">
<THEAD>
<TR VALIGN="BOTTOM">
<TH CLASS="first">Character Shading<BR>With a Vertical Line</TH>
<TH>Character Shading<BR>With a Horizontal Line</TH>
</TR>
</THEAD>
<TBODY>
<TR>
<TD CLASS="first">W(S'&lt;character&gt;'(X)[&lt;X position&gt;])</TD>
<TD>W(S'&lt;character&gt;'[&lt;Y position&gt;])</TD>
</TR>
</TBODY>
</TABLE></DIV>
<P>where</P>
<DIV CLASS="example"><P><B>S</B> identifies the shading control option.</P>
<P><B>' '</B> are single or double quotation marks that enclose the selected shading character.</P>
<P><B>&lt;character&gt;</B> selects the character cell to use for shading.</P>
<P><B>(X)[&lt;X position&gt;]</B> selects a vertical shading reference line and indicates
what X-coordinate value to use for that line.</P>
<P><B>[&lt;Y position&gt;]</B> selects a horizontal shading reference line and indicates
what Y-coordinate value to use for that line.</P></DIV>
<H3 ID="S3.7.4">Shading Complex Figures</H3>
<P>ReGIS always uses a reference line for shading. For some complex images, you
must use more than one shading reference line. You can use the following
method to shade complex graphic images.</P>
<P CLASS="note">NOTE: Digital recommends you use the polygon fill command to shade complex
figures. For shading complex figures, the polygon fill command is easier
and more efficient than the shading option. See <A HREF="chapter11.html">Chapter 11</A>.</P>
<P>Draw the shaded graphic image in two or more sections. Use different shading
reference lines for each section. Include both horizontal and vertical shading
reference lines, if needed.</P>
<P><A HREF="#F3-23">Figure 3-23</A> shows an attempt to draw a star with only one shade value and
one reference line. First, the star is drawn with a dim gray shade (I1). Then the
outline of the star is drawn with shading off.</P>
<P><A HREF="#F3-24">Figure 3-24</A> takes the same basic example and breaks the image into sections,
adding commands that define a second reference line and a second shade value.
This figure shows one way to shade a complex graphic image. You can use
other commands to draw a star.</P>
<DIV CLASS="centrefig"><TABLE ID="F3-23" CLASS="figure" WIDTH="480">
<CAPTION>Figure 3-23 Incorrect Shading of Complex Graphic Image</CAPTION>
<COL ALIGN="CENTER">
<TBODY>
<TR>
<TD><IMG SRC="ma-0702-83r.png" ALT=""></TD>
</TR>
<TR>
<TD ALIGN="LEFT"><SMALL>NOTE:<BR>
Graphic assumes all output map values are at default shades, background intensity is S(I3), and
write controls are W(F3,N0,V,I0,P1(M2)).<BR>&nbsp;</SMALL></TD>
</TR>
<TR>
<TD><TABLE CLASS="command-example" FRAME="BORDER" RULES="GROUPS" CELLSPACING="0" CELLPADDING="8">
<TBODY>
<TR>
<TD ALIGN="CENTER">COMMANDS</TD>
</TR>
</TBODY>
<TBODY>
<TR VALIGN="TOP">
<TD>P[500,200]<BR>W(S1)<BR>V(W(I2))<BR>[-100]<BR>[-50,-100]<BR>[-50,+100]<BR>
[-100]<BR>[+100,+50]<BR>[-50,+125]<BR>[+100,-75]<BR>[+100,+75]<BR>[-50,-125]<BR>
[+100,-50]<BR>W(S0)<BR>V[-100]<BR>[-50,-100]<BR>[-50,+100]<BR>[-100]<BR>[+100,+50]<BR>
[-50,+125]<BR>[+100,-75]<BR>[+100,+75]<BR>[-50,-125]<BR>[+100,-50]</TD>
</TR>
</TBODY>
</TABLE></TD>
</TR>
</TBODY>
</TABLE></DIV>
<TABLE ID="F3-24" CLASS="figure" WIDTH="100%">
<CAPTION>Figure 3-24 Complex Graphic Shading Example</CAPTION>
<COL ALIGN="CENTER">
<TBODY>
<TR>
<TD><IMG SRC="ma-0703-83.png" ALT=""></TD>
</TR>
<TR>
<TD><TABLE CLASS="command-example" FRAME="BORDER" RULES="GROUPS" CELLSPACING="0" CELLPADDING="8">
<TBODY>
<TR>
<TD ALIGN="CENTER">NOTE</TD>
</TR>
</TBODY>
<TBODY>
<TR VALIGN="TOP">
<TD>Graphic assumes all output map values are at default<BR>shades, background intensity
is S(I0), and write controls<BR>are W(F3,N0,V,P1(M2)).</TD>
</TR>
</TBODY>
</TABLE></TD>
</TR>
</TBODY>
</TABLE>
<H2 ID="S3.8">Write Control Command Summary</H2>
<P><A HREF="#T3-6">Table 3-6</A> is a summary of the <B>W</B> command options, including any default
values.</P>
<TABLE ID="T3-6" CLASS="summarytable" FRAME="VOID" RULES="GROUPS" CELLSPACING="0" CELLPADDING="4">
<CAPTION>Table 3-6 Write Control Command Summary</CAPTION>
<COL SPAN="2" WIDTH="25%">
<COL WIDTH="50%">
<THEAD>
<TR VALIGN="BOTTOM">
<TH>Option</TH>
<TH>Default</TH>
<TH>Description</TH>
</TR>
</THEAD>
<TBODY>
<TR VALIGN="TOP">
<TD>(M&lt;n&gt;)</TD>
<TD>1</TD>
<TD><P><STRONG>PV multiplication</STRONG><BR>
Defines a multiplication factor of &lt;n&gt; for all pixel vector (PV) values used in later commands.
Can serve as a temporary write control for other types of commands.</P></TD>
</TR>
<TR VALIGN="TOP">
<TD>(P&lt;0 to 9&gt;)</TD>
<TD>1</TD>
<TD><P><STRONG>Select standard pattern</STRONG><BR>
Selects 1 of 10 stored writing patterns.</P></TD>
</TR>
<TR VALIGN="TOP">
<TD>(P&lt;binary&gt;)</TD>
<TD>1</TD>
<TD><P><STRONG>Specify binary pattern</STRONG><BR>
Lets you create your own writing pattern, up to 8 bits in length.</P></TD>
</TR>
<TR VALIGN="TOP">
<TD>(P(M&lt;1 to 16&gt;))</TD>
<TD>2</TD>
<TD><P><STRONG>Pattern multiplication</STRONG><BR>
Selects how many consecutive pixels &lt;1 to 16&gt; to write each bit off pattern memory to.
You can use this option in three ways.</P>
<UL>
<LI>with the select standard pattern option</LI>
<LI>with the specify binary pattern option</LI>
<LI>by itself, to define a multiplication factor for the last specified pattern</LI>
</UL></TD>
</TR>
<TR VALIGN="TOP">
<TD>(I&lt;0 to 3&gt;)<BR>(I&lt;0 to 15&gt;)</TD>
<TD>3 (VT330)<BR>7 (VT340)</TD>
<TD><P><STRONG>Select foreground intensity or color</STRONG><BR>
Selects the output map address (&lt;0 to 3&gt;) to use for writing.</P></TD>
</TR>
<TR VALIGN="TOP">
<TD>(I(&lt;RGB&gt;))</TD>
<TD>Current color map</TD>
<TD><P><STRONG>Select foreground intensity or color (RGB)</STRONG><BR>
Selects the output map address to use for color writing with RGB values.
Selects the color closest to the RGB value specified.</P></TD>
</TR>
<TR VALIGN="TOP">
<TD>(I(&lt;HLS&gt;))</TD>
<TD>None</TD>
<TD><P><STRONG>Select foreground intensity or color (HLS)</STRONG><BR>
Selects the output map address to use for color writing with HLS values.
Selects the color closest to the HLS value specified.</P></TD>
</TR>
<TR VALIGN="TOP">
<TD>(F&lt;0 to 3&gt;)<BR>(F&lt;0 to 15&gt;)</TD>
<TD>3 (VT330)<BR>15 (VT340)</TD>
<TD><P><STRONG>Plane select</STRONG><BR>
Selects which of the terminal's bitmap planes ReGIS can write to.</P></TD>
</TR>
<TR VALIGN="TOP">
<TD>(V,R,C, or E)</TD>
<TD>(V)</TD>
<TD><P><STRONG>Writing style</STRONG><BR>
Default style is (V) for overlay writing.</P>
<P>(R) for replace writing<BR>(C) for complement writing<BR>(E) for erase writing</P></TD>
</TR>
<TR VALIGN="TOP">
<TD>(N&lt;0 or 1&gt;)</TD>
<TD>0</TD>
<TD><P><STRONG>Negative pattern control</STRONG><BR>
When set to (N1), reverses the effect of currently selected write pattern.</P></TD>
</TR>
<TR VALIGN="TOP">
<TD>(S&lt;0 or 1&gt;)</TD>
<TD>0</TD>
<TD><P><STRONG>Shading on/off control</STRONG><BR>
When set to (S1), turns on shading with currently selected pattern. The shading reference line is
defined by the Y-coordinate of the active position when (S1) is selected.</P></TD>
</TR>
<TR VALIGN="TOP">
<TD>(S[,Y])</TD>
<TD>Current Y position</TD>
<TD><P><STRONG>Select horizontal shading reference line</STRONG><BR>
Selects a line defined by [,Y], which can be either an absolute or relative value.</P></TD>
</TR>
<TR VALIGN="TOP">
<TD>(S(X)[X])</TD>
<TD>Current X position</TD>
<TD><P><STRONG>Select vertical shading reference line</STRONG><BR>
Selects a line defined by [X], which can be either an absolute or relative value.</P></TD>
</TR>
<TR VALIGN="TOP">
<TD>(S'&lt;character&gt;')</TD>
<TD>None</TD>
<TD><P><STRONG>Select shading character</STRONG><BR>
Selects a character to use for shading, instead of writing pattern.</P></TD>
</TR>
</TBODY>
</TABLE>
<DIV CLASS="navbar"><HR>
<TABLE WIDTH="100%">
<COL SPAN="3" WIDTH="33%">
<TBODY>
<TR>
<TD ALIGN="LEFT"><A HREF="chapter2.html">Chapter 2</A></TD>
<TD ALIGN="CENTER"><A HREF="contents.html">Contents</A></TD>
<TD ALIGN="RIGHT"><A HREF="chapter4.html">Chapter 4</A></TD>
</TR>
</TBODY>
</TABLE>
<DIV CLASS="navbot">http://vt100.net/docs/vt3xx-gp/chapter3.html</DIV></DIV>
</BODY>
</HTML>
